Helical Slot Antenna for the Microwave Ablation

Abstract

In this study, a thin coaxial antenna for microwave ablation (MWA) is proposed. A helical slot is added between two slots in order to overcome the disadvantage of the radiation range extending to the unwanted part in the conventional single-slot and double-slot applicators. By adding a helical slot, the specific absorption rate (SAR) pattern is more concentrated near the slot as compared with the conventional slot. Experiments were conducted using the simulation, and a liver phantom was made and heated up using microwaves. Based on the results on the liver phantom, experiments were conducted using swine liver which is similar to human liver. Applied frequency and microwave average input power were assumed as 2.45 GHz and 50 W (47 dBm), respectively. As a result of the experiment, return loss was −23.09 dB, and the temperature reached 60°C after 90 seconds of exposition. Based on the phantom experiments of the swine liver, necrotic lesions of the tissue at a distance of 3.5–4 cm from the microwave antenna were observed.